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Injuries to the Growth Plate in Children: Why are they Important?

Children’s bones face the same propensity for injury and fracture as adults though the bones of children have are viewed in a very different manner as they are still dynamic with growth until sometime between 15-18 years of age when the physis or “growth plate” fuses and their injury approaches that of their adult counterparts.

Growth plate injury can cause long-term stunting of growth or deformity. Fractures affecting the growth plate account for 35% of all skeletal injuries in children. These growth plates are in all of the long bones of the body, from fingers to toes. Most long bones in the body have at least 2 growth plates, one at the proximal end of the bone ( the part closest to the core) and one at the distal end (the end furthest from our core)

To get an understanding of the anatomy, let us take the femur or “thighbone” as an example. The femur has a proximal end, in the hip and a distal end in the knee. The bone has 2 growth plates which will appear on radiographs as non-ossified tissue, further hindering exam in many cases. The proximal growth plate of the femur has 2 “sides” the side of the shaft or the “metaphysis” and the side on the terminal side of the bone the “epiphysis”, these terms are very important in identification and implications for treatment. This may be thought of a “sandwich” with the cartilage growth plate in the middle, which is under the dynamic hormonal influence to growth during childhood and adolescence. A classification system termed the Salter –Harris classification exists to determine uniform criteria, identify the fracture (from I to V) and will be discussed a bit later.

With children’s presence in team sports as well as the prevalence of general trauma children, they are at risk of a growth plate injury or fracture that involves the growth plate. Some 10-30% of fractures in children and adolescents involve the growth plate and it is important that it always be thought of and excluded or managed as if there is an injury that is not readily apparent in children with pain with movement of an extremity. Boys are twice as likely to sustain a fracture of this type. Growth plate injury usually comes from falls, trauma involved in playing team sports such as football. Injury to the growth plate can occur due to overuse injury as well in the case of say distance runners or gymnasts. Sadly injury can occur due to child abuse and motor vehicle accidents, less likely infection of the bone.

Why do we take these injuries so seriously? Healthcare professionals take these injuries so seriously as they can cause the arrest of growth prematurely and or deformity of the limb or toe/finger.

Assessing fractures in children (in addition to many other diagnoses) is difficult at times due to a lack of history. Often times, trauma is not witnessed, and younger preverbal or newly verbal children cannot give an adequate history. A high index of suspicion is essential in children who are unwilling to bear weight on a limb or allow an extremity to be moved or manipulated.

Medical attention should be sought when:

  • the child has pain on a limb with a witnessed injury.
  • an old injury has caused a reluctance to use the extremity in play
  • there is any new deformity of the limb
  • the child is unable to move due to pain
  • there is pain in an extremity that has been overused

A child or adolescent should not be advised to “work through the pain”.

Tips on diagnosis of growth plate injuries

  • Obtain what information is possible from the child/parent/caregiver
  • A methodical and comprehensive physical exam checking one joint at a time for swelling, the range of motion and pain. Observation of gait.
  • Radiographs (which are often non-diagnostic as the growth plate has not ossified yet) of bilateral joints/limbs for comparison.
  • MRI may be used for suspicious cases to better delineate the growth plate or at times CT scan.
  • Timing is critical. Given children quick healing and one would not want maladaptive healing to take place, if too much time has elapsed before reduction if required
  • The reduction should be performed in the hands of an experienced pediatric orthopedist. The reduction will require sedation as children will rarely cooperate with this ( manipulating the edges into alignment) it should be done swiftly and ideally on the first attempt, as the delicate cartilage may be further damaged by repeat attempts.
  • Appropriate Emergency Department Care involves splinting and prompt pediatric orthopedic evaluation cases of questionable growth plate fractures. Analgesia and decreased the range of motion and weight-bearing restriction.

How should they be treated?

Management depends on the classification and the extent of the injury. However, management is similar to adult fractures, displaced fractures require reduction or manipulation either while the child sedated or surgically, with open reduction and internal fixation with plates and screws in the operating room. Immobilization is then required with a cast that extends beyond the above and below joint. Some fractures heal quickly in weeks, others take months. These children will require follow-up of symmetric radiographs, for years to check for any growth delay. The vast majority do well while those with compromised blood supply carry a worse prognosis. The downfall in evaluation is a failure to consider an SH fracture or growth plate injury in a normal radiograph.

The growth plates show up on X-ray because they are made of cartilage, which is 'radio-lucent', and the X-ray reveals only the space that the cartilage occupies.

Salter-Harris Classification of pediatric fractures

I

  • Described as 'slipped'
  • Fracture plane all the way through the growth plate NOT involving bone
  • 5-7%. Good Prognosis

II

  • Fracture passes all the way through the growth plate and the metaphysis (above growth plate)
  • Most common at 75%. Good Prognosis

III

  • Fracture across the most of the growth plate and down through the epiphysis (below the growth plate)
  • 7-10%
  • Poorer prognosis

IV

  • 'through' or transverse. Fracture extends through the metaphysis, epiphysis and growth plate
  • 10% of all SH fractures
  • Poor prognosis

V

  • 'crushed', resulting from a crush injury, blood supply often altered. Delicate cartilage is damaged across the extent of the growth plate.
  • Worst prognosis